Today I replaced a 'squared off" Gator HardShell with close to 2300 miles with a new one. Didn't figure that another 15%-20% of mileage would be worth an episode or two of standing beside the road while replacing a tube.

Using a micrometer I measured the thickness of the old and new tire and found that the old tire is .102" thick at the contact point and the new is .144. Assuming typical Germanic consistency (Continental Tire), the tire was mostly clapped out with a tread wear of 42 thousandths of an inch (.042"). And that's a relatively heavy tire!

Not much tread on these tires. And they say to replace your car tire when it gets to the thickness of a penny. That's about triple the tread depth of a new bike tire.

Bike tires do not hydroplane, and, for a road bike, no "tread" is necessary. In fact, many believe a smooth tire with no tread performs better, including "traction".

Sorry, didn't make myself clear, didn't mean tread per se but rubber covering over the tire cords.

I think you did the right smart thing changing when you did. Some people like to squeeze the last mile out of a tire and could wind up on the side of the road with a blow out and have to boot the tire to get back. You could ask me how I know. LOL.

Welllll, I always ride mine down till the cords start showing, pretty much. The last tire I replaced hadn't quite gotten down to the cords when it got a ~3/8" cut in the sidewall on a recent ride. Drat.

I'm convinced that when we're all dead and gone, victims of the Zombie Apocalypse, that my Schwalbe Marathon tires will still have plenty of tread on them.

You may be over-thinking this tire replacement thing. I buy top quality tires, then run them into the ground or until they are not reasonable to ride due to cuts. If I haven't had a problem with cuts, I ride them until the first signs of the casing begining to show.

The thinner the rubber and the easier it is for "Foreign objects to penetrate. Never measured the depth left on tyres when I change them but they feel pretty thin when I do. Just got rid of a couple of NEW OM tyres that came on the Pinnie as the amount of rubber on them from new was less than I would have on a used tyre when it is discarded. Reason for getting them off the bike was 2 punctures in one ride.

I suppose the engineer gene in me is what makes me change tires as you do Tom. I use visual inspections for daily judgement, looking for cuts early on, and later measure them when I service the wheel set. I can't ride a really worn tire to save me. they don't cost much and I really hate walking and/or carrying a bicycle.

Bill

+1

Peace of mind is worth much more to me than riding an extra 500 miles on an "iffy" tire.

Agreed, to each their own I suppose.

Bill

I buy tires on sale and have extras around. The less thread, the greater the chance of flats. So I replace them probably well before I really need to but I also had only one flat in the last year.

Some tires get superficial cuts easily like Michelin, Conti, and a few models Specialized. These really don't do anything and mostly are related to the softer compound.

BTW, I use mostly Conti GP 4000 and they have wear indicator holes on the thread.